Shirra began riding at the Kembla Grange Speedway in New South Wales in 1973 at the age of 14 (he lied about his age in order to race as riders had to be at least 16 years old), although he would consider the Liverpool Speedway in Sydney as his home track.[3] Early in his career this actually led him to ride as an Australian rider, though by the late 1970s when his true age and nationality was revealed he would be considered a New Zealand rider.[citation needed]
In 1975, Shirra joined the Coventry Bees[4] and was loaned out to the Coatbridge Tigers for a year. From 1976 to 1982, he rode for Coventry[5] then transferred to the Reading Racers. In 1987, he was loaned out to the Swindon Robins but returned to Reading in 1988–1989. In 1990 he was banned from the British League for a season for bringing the sport into disrepute after failing two drug tests. Controversy about the decision soon followed and the ban was lifted by the speedway control board. After three months, Shirra returned to racing for the remainder of the 1990 season.[6] He returned to race for Reading in 1991, Swindon in 1992, the Ipswich Witches in 1993 and 1994 he was awarded best club rider that season.[citation needed]
Shirra competed in his first individual World Final in 1983 at the Motodrom Halbemond in Norden, West Germany where he finished in 11th place having scored 7 points. He was again a World Finalist in 1984 at the Ullevi Stadium in Gothenburg, Sweden where he scored 10 points for a career best 5th place. He would go on to ride in another five World Finals during his career (1986, 1987, 1989, 1991 and 1992). He was 6th at the Munich Olympic Stadium in 1989.
In 1984, Shirra finished 3rd in the World Pairs Championship with Ivan Mauger in Lonigo, Italy. Devastation soon followed his success towards the end of 1984. During an open meeting at Western Springs in Auckland, Shirra sustained a shattered pelvis and femur along with internal injuries.[citation needed] It was feared he would not return to racing but after a lengthy recovery he did return, and continued to have much success and countless podium finishes at a British/European and international level. One of his biggest wins would come when he won the Overseas Final at the Odsal Stadium in Bradford in 1987. In 1988, he controversially was seeded through to the Commonwealth final by the New Zealand ACU, despite failing to qualify from the New Zealand round of the world championship.[14]
In 1990, Shirra was named as the team manager for the World All-Stars team who took on England in a 3 match Sidecar speedway series ran in England. The World team consisted mostly of those from his native New Zealand as well as Australia.[15]
Shirra is also a three time New Zealand Champion, having won the title in 1982 (Western Springs), 1983 (Ruapuna Speedway), and 1984 (Penlee Speedway). He finished runner-up in the NZ Championship in 1979, 1981 and 1987, while finishing third in 1986.
* Australian rider and meeting reserve Phil Herne rode one race as Larry Ross had bike trouble ** Australian rider Alan Rivett replaced the injured David Bargh
